walter sondheim, fvtx review nov 12 th,2008 1 fvtx mechanical status : walter sondheim - lanl...

Walter Sondheim, FVTX Review Nov 12th,2008 1

FVTX Mechanical Status:

Walter Sondheim - LANL Mechanical Project Engineer; VTX &

FVTX


Mechanical Design Philosophy:

• The Design of the FVTX structures and services have been driven by the following requirements;– High mechanical and thermal stability. – Radiation tolerance up to an integrated dose over 10

years of 300 – 500 krads in the region of the detectors and 200 krads in the region of the ROC (read-out-card).

– High transparency to particles, keep the radiation length to a minimum, especially the material mass that is in the acceptance.

– Silicon modules to be maintained at room temperature or slightly lower, sensor electronics has low susceptibility to radiation damage.

– Very low maintenance over 10 year expected lifetime.– High granularity of the services to increase the reliability

of the operation.– Modular Assembly.


VTX-FVTX Half Assembly for Introduction:

Two half FVTX detectors

Beryllium beam-pipe, 41.021 mm OD X 800.0 mm long

VTX detector, 4 layers; inner 2 pixels, outer two strip-pixel sensors

Big Wheel region; read-out electronics for VTX&FVTX

Support structure and isolation mounts attached to central magnet


Sensor Module: Two variations for stations2 & 3, upstream and downstream:

Upstream Downstream

POCO graphite support block with pin hole for alignment, screw hole for mounting

PEEK support block with pin hole for alignment and screw hole for mounting

Graphite back-plane 1.56 mm, K13C2U carbon fiber, Cyanate Ester resin, fabrication at LBNL

HDI .44 mmSensor

.32 mm

FPHX chips bonded to HDI

Mounting screw location

Mounting screw location

HDI connectors to extension cable to ROC

Bonding of FPHX chips to HDI use Arclad 8026 transfer adhesive, 1 mil

Bonding of silicon sensor to carbon backplane Arclad 8026 and Tra-bond 2902 silver epoxy


Half-Station sub-assembly, stations 2, 3 or 4:

Mounting and alignment pins in tabs, 3 per station half disk

Thermally conductive block to transfer heat from wedge to support panel

Nylon mounting screw – (phillips head)

Graphite faced support panel

Four layers of 15 degree wedges, 2 layers on each side of support panel

Each wedge staggered in Z, 15 degrees between wedges on one side, upstream to downstream sides of panel offset by 7.5 degrees – hermetic in phi. Each silicon sensor covers 7.5 degrees in phi.


Support Panel Construction:

Hose barb PEEK

Insert for screws and pins - PEEK

Wedge locating pin

Mounting tab

GFRP face sheet, .25 mmCore – foam, 4.76 mm

Core insert, pins and screws, PEEK

Cooling channel, PEEK

GFRP face sheet, .25 mm

Fabrication of disk assembly will take place at LBNL composite shop

Holes for survey flag along edge


Half Cage Assembly with Liquid Cooling Circuit:

Each station is cooled in parallel with the other stations.

Inlet temperature 0 – 10 degrees C, delivery pressure 5 psi

Delta-T per ½ station 1.8 degrees C, delta p .4 psi

Coolant 3M Novec 7200

Inlets

Outlets

Novec 7200:

Boiling point 76 degree C

Melting point -138 degree C

Vapor pressure 109 mmHg @ 25 degrees C

Neutron irradiation study at LANL’s WNR facility – total dose 6.7 X 10**11 n/cm**2, nominal energy 800 Mev. Samples were sent to 3M for analysis of free Flouride, no indication of significant degredation.


FVTX Cage:

Cage design uses CN60 carbon fabric with a EX1515 resin. FEA analysis indicates very rigid structure < 25. microns.

Blocks and flanges POCO graphite ACF-100Q.

Note: the mounting blocks for the 4 stations will be clocked in 1 degree increments.

Each FVTX interfaces directly with the VTX space-frame.

For scale: 400. mm in diameter, 187. mm in length.

Penetrations in shell for survey/alignment flags

Fabrication will take place at LBNL composite shop.


Coolant to FPHX Chips Thermal Path – 2007 review – current changes:

• Use Simple Correlations to Evaluate– Pressure drops

– Temperature drop from fluid to cooling tube

Approximate temperatures with 10°C coolant flowing at Re~10,000(0.76mm K13CU backplane, 50μm Nickel tube, 0.2 W/mK epoxy, 0.75 W/mK silicone)

Inside of F.S: 11.7°C

Top of thermal bridge: 12.5°C

Warmest FPHX: 19.3°C

Tube wall: 11.6°C

HDI

Panel core (Al HC)

Bulk coolant: 10°C

Back of wedge backplane: 15°C

Inn

er

Radiu

s

FoamThermally Conductive Epoxy

Thermally Conductive Silicone

Outside of F.S: 12.2°C

Oute

r R

adiu

s

Bottom of thermal bridge: 12.3°C

Backplane

Cooling tube

Thermal bridge

Thermally conductive silicone

Thermally Conductive Epoxy

2008 Changes to Wedge:

FPHX readout chip power increased 100 to 600 micro-watts per chip.

Rerun thermal model and FEA analysis over next month

Thicker 2X

Thicker 2.5X

Channel

POCO graphite

Arclad 8026 transfer adhesiveFoam

PEEK


Large Station and Cage-Level Modeling:

Fundamental Vibration ModeDistortion due to Cooling(assembled at room temperature)

Max deflection ~ 21μmMax deflection within active area ~ 8μm

138Hz


Measurement of Central magnet vibration;

•Vibration Level Threshold 1*E-8 g2/Hz•Accelerometer Noise Floor 1*E-11 g2/Hz•Peak Measured Vibration 1.2*E-9 g2/Hz

• Vibration measurements were made on the Central magnet pole tips to see if mounting the VTX-FVTX vertex detectors off the pole tips would induce unwanted vibrations to the operation of this detector system.

• A comparison of the vibration levels measured and the threshold levels calculated – showed that the peak vibration levels are 10X lower than the threshold value.

• The measurements made in the PHEINX IR were successful at collecting sufficient data to conclude that the vibration levels on the support rails would not adversely affect the performance of the vertex detector system.


Two Independent Halves:

“Big Wheel” cooling plate with coolant channel along perimeter, 3. mm Aluminum

ROC cards, 38. watts/card

Gas seal between layers

Wedge readout extension cables

This half FVTX assembly is stand alone, can be tested independently of the rest of the detector in a lab.


Model heat transfer in lab:

• Model heat transfer in wedge assembly• Model heat transfer from ROC cards to cooling plate

Watlow heater 75 watt


Summary: WBS 1.6 Mechanics – Schedule Dates & Manpower

• WBS 1.6 10/21/2005 – 9/29/2009– WBS 1.6.1 Specifications 10/21/2005 – 2/9/2006– WBS 1.6.2 Support Structure Cage 4/1/2007 –

12/25/2009– WBS 1.6.3 Wedge Backplane 4/11/2008 – 6/19/2009– WBS 1.6.4 Support Disk 1/4/2007 – 8/28/2009 – WBS 1.6.5 Alignment and Assembly 8/1/2008 – 3/5/2009

• Manpower– 1 engineers– 1 physicist liaison– HYTEC:

• 1 Engineer• 1 Designer

walter sondheim, fvtx review nov 12 th,2008 1 fvtx mechanical status : walter sondheim - lanl...

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